How to randomize json

I have a randquotes.json file

{
    "author": "William Shakespeare",
    "quotes": "A brave flea is a flea that can dare to get its breakfast on the lips of a lion."
},
{
    "author": "Winston Churchill",
    "quotes": "We live with what we get, but we bring life to what we give."
},
{
    "author": "Wolfgang von Gothe",
    "quotes": "Knowledge is not enough, we must practice it. Intention is not enough, we must do it."
}

Then I want "author" and "quotes" to be generated randomly with php

How? thanks for help